Multi-lobe balloon for cryoablation

ABSTRACT

A cryotreatment catheter for treating tissue. The catheter may include an outer elongate body, a balloon treatment element coupled to the distal portion of the elongate body with a plurality of balloon lobes radially arranged around the outer elongate body, an inner elongate body rotatably movable within the lumen of the outer elongate body, and a fluid delivery lumen located within the lumen of the outer elongate body and at least partially within the lumen of the inner elongate body. The fluid delivery lumen may be branched at a distal portion into a plurality of linear segments, each linear segment being in fluid communication with one of the plurality of balloon lobes. Each of the balloon lobes may be inflated independently of each other by the linear segments of the fluid delivery lumen.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of patent application Ser. No.15/988,431, filed May 24, 2018, now U.S. Pat. No. 10,299,848, issued May28, 2019 entitled MULTI-LOBE BALLOON FOR CRYOABLATION and is acontinuation of and claims priority to patent application Ser. No.14/944,870, filed Nov. 18, 2015, now patent Ser. No. 10/058,371, issuedAug. 28, 2018 entitled MULTI-LOBE BALLOON FOR CRYOABLATION, the entiretyof which is incorporated herein by reference.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

n/a

TECHNICAL FIELD

The present invention relates to an adjustable treatment device foraccommodating a variety of pulmonary vein morphologies and a method ofablating tissue using the same.

BACKGROUND

A cardiac arrhythmia is a condition in which the heart's normal rhythmis disrupted. Certain types of cardiac arrhythmias, such as paroxysmalatrial fibrillation, may originate from an arrhythmogenic focus in orclose to the pulmonary veins. Recent studies of pulmonary vein (PV)morphology showed that there is a wide variability in, for example, PVdiameters at the ostia between the position of the veins within the samepatient's heart (right superior PV, left superior PV, right inferior PV,and left inferior PV). These studies also showed that the diameter andcross-sectional area of the left superior PV are gender dependent, beingsignificantly larger in men than in women.

Many types of cardiac arrhythmia may be treated by various ablationmethods, including cryoablation. Data analysis of cryotherapy proceduresshowed that the use of cryoballoon catheters in combination with focalor radiofrequency (RF) catheters is common. Generally speaking, thefocal or RF catheters are used to access sections of the PVs at theostia that are inaccessible using only the cryoballoon catheter or thatstill exhibit conduction of aberrant electrical signals aftercryoballoon ablation. The average rate of using such touch-up methodsfor three consecutive years was about 11% (2011, 2012, and 2013).

Given the variation in PV morphology between patients of differentgenders and, indeed, within a single patient, means that treatingarrhythmia using a one-size-fits-all cryoballoon catheter without theneed for one or more touch-up procedures is nearly impossible. As theneed for focal or RF catheter ablation following cryoablation poses asafety risk to the patient and increases procedure time, it is desirableto provide a cryoablation device that can be adjusted to accommodate avariety of PV morphologies, such as PV diameter, cross-sectional area,shape, etc.

SUMMARY

The present invention advantageously provides a device and system thatis adjustable for accommodating a variety of pulmonary vein morphologiesand a method of ablating tissue using the same. A cryotreatment cathetermay generally include an elongate body including a distal portion, aproximal portion, and lumen therebetween, and a balloon treatmentelement coupled to the distal portion of the elongate body, the balloontreatment element including a plurality of balloon lobes radiallyarranged around the elongate body. For example, the balloon treatmentelement may include at least six balloon lobes. The distal portion ofthe elongate body may include a first plurality of apertures and asecond plurality of apertures located distal to the first plurality ofapertures, each of the first and second pluralities of apertures beingradially arranged around the elongate body and corresponding to one ofthe plurality of balloon lobes. Each of the plurality of balloon lobesmay include a first aperture that is radially aligned with one of theplurality of first apertures of the elongate body, and a second aperturethat is radially aligned with one of the plurality of second aperturesof the elongate body, the second aperture being located distal to thefirst aperture. The elongate body may be an outer elongate body, and thecryotreatment catheter may further include an inner elongate bodyincluding a distal portion, a proximal portion, a lumen therebetween,and a plurality of apertures radially arranged around the inner elongatebody. Each of the plurality of apertures of the inner elongate body maycorrespond to one of the first plurality of apertures of the outerelongate body. Further, the distal portion of the inner elongate bodymay define a distal end, the distal end of the inner elongate body beingdistal to the first plurality of apertures of the outer elongate body.The cryotreatment catheter further may include a delivery lumen at leastpartially located within the inner elongate body. The delivery lumen mayinclude a proximal portion located within the inner elongate body, and abranched distal portion located within the outer elongate body distal tothe distal end of the inner elongate body, the branched distal portionincluding a plurality of linear segments, each of the plurality oflinear segments being in fluid communication with a corresponding one ofthe plurality of balloon lobes. Each of the linear segments may includea distal tip portion that has a delivery aperture, each of the distaltip portions extending from a corresponding linear segment at anapproximately 90° angle, each of the distal tip portions extendingthrough a corresponding one of the second plurality of apertures of theouter elongate body and a corresponding second aperture of one of theplurality of balloon lobes. The lumen of the outer elongate body may beconfigured to be in fluid communication with a vacuum source and a fluidreservoir.

A cryotreatment catheter may include: an outer elongate body including adistal portion, a proximal portion, and a lumen extending between thedistal portion and the proximal portion, the distal portion defining adistal end; a balloon treatment element coupled to the distal portion ofthe elongate body, the balloon treatment element including a pluralityof balloon lobes radially arranged around the outer elongate body; aninner elongate body located within and rotatably and/or linearly movablewithin the lumen of the outer elongate body, the inner elongate bodyincluding a distal portion, a proximal portion, and a lumen extendingbetween the distal portion and the proximal portion, the distal portiondefining a distal end that is located proximal to the distal end of theouter elongate body; a fluid delivery lumen located within the lumen ofthe outer elongate body and at least partially within the lumen of theinner elongate body. The outer elongate body may include a firstplurality of apertures and a second plurality of apertures locateddistal to the first plurality of apertures, each of the first and secondpluralities of apertures being radially arranged around the elongatebody and corresponding to one of the plurality of balloon lobes, each ofthe plurality of balloon lobes may include a first aperture that isradially aligned with one of the plurality of first apertures of theelongate body, and a second aperture that is radially aligned with oneof the plurality of second apertures of the elongate body, the secondaperture being located distal to the first aperture. The inner elongatebody may include a plurality of apertures radially arranged around theinner elongate body, each of the apertures of the inner elongate bodycorresponding to one of the first plurality of apertures of the outerelongate body. The plurality of balloon lobes may include at least sixballoon lobes. The fluid delivery lumen may include: a proximal portionlocated within the inner elongate body; a branched distal portionlocated within the outer elongate body, the branched distal portionincluding a plurality of linear segments, each of the plurality oflinear segments being in fluid communication with a corresponding one ofthe plurality of balloon lobes; and a divergence point between theproximal portion and the branched distal portion, the divergence pointbeing distal to the distal end of the inner elongate body. Each of thelinear segments may include a distal tip portion that has a deliveryaperture, each of the distal tip portions extending from a correspondinglinear segment at an approximately 90° angle, each of the distal tipportions extending through a corresponding one of the second pluralityof apertures of the outer elongate body and a corresponding secondaperture of one of the plurality of balloon lobes. Each of the outerelongate body and the inner elongate body may include a longitudinalaxis, the longitudinal axis of the inner elongate body being coaxialwith the longitudinal axis of the outer elongate body, and the innerelongate body is configured to obstruct the first plurality of aperturesof the outer elongate body when the inner elongate body is rotatedand/or linearly moved along its longitudinal axis.

A cryotreatment catheter may include: an outer elongate body including alongitudinal axis, a distal portion, a proximal portion, and a lumenextending between the distal portion and the proximal portion, thedistal portion defining a distal end, the outer elongate body furtherincluding a first plurality of apertures and a second plurality ofapertures located distal to the first plurality of apertures; a balloontreatment element coupled to the distal portion of the elongate body,the balloon treatment element including a plurality of balloon lobesradially arranged around the outer elongate body, each of the pluralityof balloon lobes having an attachment spine and a tissue contactsurface, a first plurality of apertures, and a second plurality ofapertures located distal to the first plurality of apertures, the firstplurality of apertures of the balloon lobes being radially aligned withthe first plurality of apertures of the outer elongate body and thesecond plurality of apertures of the balloon lobes being radiallyaligned with the second plurality of apertures of the outer elongatebody; an inner elongate body located within and rotatably movable withinthe lumen of the outer elongate body, the inner elongate body includinga longitudinal axis that is coaxial with the longitudinal axis of theouter elongate body, a distal portion, a proximal portion, a lumenextending between the distal portion and the proximal portion, and aplurality of apertures at the distal portion, the distal portiondefining a distal end that is located proximal to the distal end of theouter elongate body, and the plurality of apertures of the innerelongate body being configured to be radially aligned with the firstplurality of apertures of the outer elongate body and the firstplurality of apertures of the balloon lobes, the inner elongate bodybeing configured to obstruct the first plurality of apertures of theouter elongate body when the inner elongate body is rotated along itslongitudinal axis; and a fluid delivery lumen including a proximalportion, a branched distal portion, and a divergence point therebetween,the divergence point being located distal to the plurality of aperturesof the inner elongate body.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete understanding of the present invention, and theattendant advantages and features thereof, will be more readilyunderstood by reference to the following detailed description whenconsidered in conjunction with the accompanying drawings wherein:

FIG. 1 shows an exemplary system including a treatment catheter havingan adjustable balloon treatment element;

FIG. 2 shows a balloon lobe;

FIG. 3A shows a cross-sectional view of a fluid delivery lumen withinthe treatment catheter of FIG. 1;

FIG. 3B shows a close-up view of a portion of the fluid delivery lumen;

FIG. 4 shows a distal cross-sectional view of a first embodiment of theballoon treatment element with all lobes being fully inflated;

FIG. 5 shows a distal cross-sectional view of a second embodiment of theballoon treatment element with all lobes being fully inflated;

FIG. 6A shows a general inflation position of an inner lumen relative tothe balloon treatment element;

FIG. 6B shows a precision inflation position of the inner lumen relativeto the balloon treatment element;

FIG. 6C shows an ablation position of the inner lumen relative to theballoon treatment element;

FIG. 7 shows a distal cross-sectional view of a first example of anasymmetrical inflation of the balloon treatment element;

FIG. 8 shows a distal cross-sectional view of a second example of anasymmetrical inflation of the balloon treatment element;

FIGS. 9A-9D show configurations of an inner elongate body within atreatment catheter during a cryotreatment procedure; and

FIGS. 10 and 11 show cross-sectional views of thermoplastic tubes withina mold for forming the multi-lobed balloon treatment element.

DETAILED DESCRIPTION

The present invention advantageously provides a device and system thatis adjustable for accommodating a variety of pulmonary vein morphologiesand a method of ablating tissue using the same. Referring now to thedrawing figures in which like reference designations refer to likeelements, an exemplary system including a cryoablation catheter havingan adjustable cryoballoon treatment element is shown in FIG. 1 andgenerally designated as “10.” The device components have beenrepresented where appropriate by conventional symbols in the drawings,showing only those specific details that are pertinent to understandingthe embodiments of the present invention so as not to obscure thedisclosure with details that will be readily apparent to those ofordinary skill in the art having the benefit of the description herein.Moreover, while certain embodiments or figures described herein mayillustrate features not expressly indicated on other figures orembodiments, it is understood that the features and components of thesystem and devices disclosed herein are not necessarily exclusive ofeach other and may be included in a variety of different combinations orconfigurations without departing from the scope and spirit of theinvention.

The system 10 may generally include a treatment catheter 12 and acontrol unit 14 in communication with the treatment device 12. Thetreatment device 12 may be, for example, a cryoballoon catheter and thecontrol unit 14 may be configured for use with a cryotreatmentprocedure. The cryotreatment catheter 12 may include a balloon treatmentelement 18 that includes a plurality of balloon lobes 20. As isdescribed in more detail below, each of the balloon lobes 20 may beinflated and deflated independently of each other.

Referring to the treatment catheter 12 in more detail, the catheter 12may include an elongate body 24 passable through a patient's vasculatureand/or positionable proximate to a tissue region for diagnosis ortreatment, such as a catheter, sheath, or intravascular introducer. Theelongate body 24 may include a proximal portion 26, a distal portion 28,and a longitudinal axis 30, and may further include one or more lumensdisposed within the elongate body 24 that provides mechanical,electrical, and/or fluid communication between the elongate bodyproximal portion 26 and the elongate body distal portion 28. Forexample, the elongate body 24 may include a main lumen 32. The balloontreatment element 18 may be coupled to the distal portion 28 of theelongate body 24, with the plurality of balloon lobes 20 being radiallyarranged about the elongate body 24.

Continuing to refer to FIG. 1, the control unit 14 may include a fluidsupply including one or more reservoirs 36 for one or more coolants,cryogenic refrigerants, or the like, an exhaust or scavenging system forrecovering or venting expended fluid for reuse or disposal (including,for example, a recovery reservoir and vacuum pump), as well as variouscontrol mechanisms. The control unit 14 may also include an additionalfluid supply including a reservoir 38 containing a non-coolant liquid,gas, or combination liquid and gas used to inflate the balloon lobes 20,which fluid may be referred to as “inflation fluid.” In addition toproviding an exhaust function for the inflation fluid and/or refrigerantreservoirs, the control unit 14 may also include pumps, valves,controllers or the like to recover and/or re-circulate fluid deliveredto various fluid pathways of the catheter. A vacuum pump 40 in thecontrol unit 14 may create a low-pres sure environment in one or moreconduits within the catheter so that fluid is drawn into theconduits/lumens of the elongate body 24, away from the distal portion 28and toward the proximal portion 26 of the elongate body 24.

The control unit 14 may also include one or more components for themanual, automatic, and/or semi-automatic regulation of the system, suchas a computer 42 having one or more processors 44 for executing one ormore algorithms for the automatic or semi-automatic regulation of thecatheter 12 before, during, and after an ablation procedure. Forexample, the one or more processors 44 may be programmable to at leastpartially inflate and at least partially deflate the plurality ofballoon lobes 20, to regulate temperature of the balloon treatmentelement 18, and/or to receive and interpret mapping or sensor signalsfrom the cryotreatment catheter 12 or another device used as part of amedical procedure. The control unit 14 may also include, for example, aproportional valve that regulates inflation of the balloon treatmentelement 18 during the transition between the inflation phase and theablation phase. Although various system components may be shown anddescribed herein as being within the control unit 14, the term “controlunit” as used herein refers to any system component other than thecryotreatment catheter and other devices that are passed into thepatient to perform the medical procedure, regardless of whether thecomponents are physically located within the control unit 14.

Referring now to FIG. 2, the balloon treatment element 18 may be, forexample, a cryotreatment element. As shown in the figures, the balloontreatment element 18 may include a plurality of balloon lobes 20radially arranged about the elongate body 24. As a non-limiting example,the balloon treatment element 18 may include six balloon lobes, althoughfewer or more balloon lobes 20 may be included. Each of the balloonlobes 20 may include a proximal portion 48, a distal portion 50, and anattachment spine 52 proximate the elongate body 24, a tissue contactsurface 54 opposite the attachment spine 52, and each lobe 20 may definean inner chamber 56. Further, each balloon lobe 20 may include twolateral surfaces 58 that are in contact with the lateral surfaces 58 ofadjacent lobes 20. Each balloon lobe 20 may be shaped approximately likea section of an orange and the attachment spine 52 of each lobe 20 maybe affixed to the distal portion 28 of the elongate body 24. As anon-limiting example, each attachment spine 52 may be affixed proximallyto the elongate body distal portion 28 and distally to a distal tip 59using an adhesive, chemical or thermal bonding, or other suitableattachment means (for example, as shown in FIG. 1). Alternatively, eachattachment spine 52 may be affixed proximally and distally to theelongate body 24 (for example, as shown in FIGS. 3A and 9A-9D). Further,each attachment spine 52 may include a first (proximal) aperture 60 anda second (distal) aperture 62. Likewise, the distal portion 28 of theelongate body 24 may include a plurality of first (proximal) apertures64, each of which corresponding to an adjacent first aperture 60 of aballoon lobe attachment spine 52. For example, if the balloon treatmentelement 18 includes six balloon lobes 20 each having a first aperture60, the distal portion 28 of the elongate body 24 may include six firstapertures 64 that are radially arranged about the elongate body 24longitudinal axis and configured to match up with or be in fluidcommunication with each of the balloon lobe first apertures 60. Thedistal portion 28 of the elongate body 24 may further include aplurality of second (distal) apertures 66, each of which correspondingto an adjacent second aperture 62 of a balloon lobe attachment spine 52.For example, if the balloon treatment element 18 includes six balloonlobes 20 each having a second aperture 62, the distal portion 28 of theelongate body 24 may include six second apertures 66 that are radiallyarranged about the elongate body 24 longitudinal axis 30 and configuredto match up with or be in fluid communication with each of the balloonlobe second apertures 62. Each of the apertures disclosed herein may bea round or substantially round hole in the wall of the elongate body 24or the balloon lobe attachment spine 52. However, it will be understoodthat the apertures may be of any size or configuration that allows thepassage of fluid therethrough. Further, the diameter of each aperturemay be sized to provide a desired fluid flow rate.

Referring now to FIGS. 3A and 3B, the elongate body 24 may define a mainlumen 32, which may function as both an inflation lumen and an exhaustlumen. The catheter 12 may also include an inner elongate body 70defining an inner lumen 72, and the inner elongate body 70 may berotatable and/or longitudinally (linearly) movable within the main lumen32 of the elongate body 24, which may be referred to as being an outerelongate body 24 relative to the inner elongate body 70. The innerelongate body 70 may also include a plurality of apertures 74 that maybe radially and longitudinally aligned with the first apertures 64 ofthe elongate body 24 and the first apertures 60 of the balloon lobes 20,such that rotation and/or longitudinal movement of the inner elongatebody 70 in at least one direction may selectively obscure/obstruct orunobscure/unobstruct the first apertures 64 of the elongate body 24 andthe first aperture 60 of each of the balloon lobes 20. Additionally oralternatively, the inner elongate body 70 may be advanced or retractedwithin the main lumen 32 to selectively obscure/obstruct orunobscure/unobstruct the first apertures 64, 60 of the elongate body 24and the balloon lobes 20. The elongate body 24 and the inner elongatebody 70 may each define a proximal portion and a distal portion, witheach distal portion defining a distal end. The distal end 76 of theinner elongate body 70 may be at a location that is proximal to thedistal end 78 of the elongate body 24 (as shown in FIG. 3A).

The catheter 12 may also include a delivery lumen 82 that includes aproximal portion 84 and a distal portion 86. At least a portion of theproximal portion 84 of the delivery lumen 82 may be located within theinner elongate body lumen. The distal portion 86 of the delivery lumen82 may be branched into a plurality of linear segments 88, with eachlinear segment 88 being in fluid communication with one of the pluralityof balloon lobes 20 through the second apertures 66 of the elongate body24 and the second aperture 62 of the balloon lobe 20. Further, theproximal portion 84 of the delivery lumen 82 may end, and the distalportion 86 of the delivery lumen 82 may begin, at a branch or divergencepoint 90 location that is distal to the distal end 76 of the innerelongate body 70 and distal to the elongate body first apertures 64 (asshown in FIG. 3A).

As is shown in detail in FIG. 3B, each linear segment 88 of the distalportion 86 of the delivery lumen 82 may include a distal tip portionthat includes a fluid delivery segment 96. The fluid delivery segment 96extend from the linear segment 88 at an approximately 90° angle (±5°),forming an L shape. Thus, each branch of the delivery lumen distalportion 86 may be referred to herein as being “L shaped.” Each of thefluid delivery segments 96 may extend at least partially through acorresponding second aperture 66 of the elongate body 24 and a secondaperture 62 of a balloon lobe 20 to be in fluid communication with thelobe inner chamber 56. The tip of the fluid delivery segment 96 maydefine or include a delivery aperture 98, through which an inflationand/or cryogenic fluid may be delivered to the inner chamber of theballoon lobe 20. The second apertures 66 of the elongate body 24 and thesecond apertures 62 of the balloon lobes 20 may be sized and configuredsuch that they are able to receive the fluid delivery segment 96 of eachlinear segment but without allowing inflation fluid and/or cryogenicrefrigerant to leak back into the main lumen 32. For example, the fluiddelivery segment 96 may be friction fit and/or coupled within the secondaperture 66 of the elongate body 24 and the second aperture 62 of theballoon lobes 20 (such as with an adhesive, chemical or thermal bonding,or other suitable means). A proximal portion of each linear segment 88may pass through a sheath or lumen to form a bundle, or may be coupledto one another to form a bundle, and this bundle may be referred to asthe proximal portion 84 of the delivery lumen 82.

Referring now to FIGS. 4 and 5, distal cross-sectional views of twoembodiments of the balloon treatment element are shown. In the firstembodiment shown in FIG. 4, the balloon treatment element 18 may includeonly a plurality of balloon lobes 20. In the second embodiment shown inFIG. 5, however, the balloon treatment element 18 may also include anouter balloon 102 that surrounds the plurality of balloon lobes 20. Theouter balloon 102 may be composed of a material that is more compliantthan the material from which the plurality of balloon lobes 20 arecomposed, and the outer balloon 102 may help smooth the transitionalcurves between the balloon lobes 20 and create a smooth tissue contactsurface that covers all or at least substantially all of the balloontreatment element 18. The outer balloon 102 may include a distal neckand a proximal neck (not shown) that are affixed or coupled to thedistal tip 59 and the distal portion 28 of the elongate body 24,respectively. Alternatively, the outer balloon 102 may be coupled to theelongate body 24 in another suitable manner.

Although not shown, the treatment catheter 12 may also be configured foruse with other energy modalities, such as radiofrequency energy,microwave energy, laser energy, ultrasound energy, electroporationenergy, and the like. Therefore, it will be understood that the balloontreatment element 18 may also include one or more electrodes and/orother energy delivery elements. As a non-limiting example, the balloontreatment element 18 may include one or more fiber sensors locatedwithin the balloon lobes 20 and/or between the balloon lobes 20 and theouter balloon for temperature assessment of the ablated tissue and/orstrain assessment. Further, the one or more fiber sensors may be usedfor hyperspectral assessment of the targeted tissue. The medical systemmay also include one or more sensors to monitor the operating parametersthroughout the system, including for example, pressure, temperature,flow rates, volume, or the like in the control unit 14, and/or thecatheter 12. For example, the catheter 12 may further include one ormore temperature and/or pressure sensors (not shown) proximate and/orwithin the balloon treatment element 18 for monitoring, recording orotherwise conveying measurements of conditions within the medical deviceor the ambient environment at the distal portion of the medical device.The sensor(s) may be in communication with the control unit 14 forinitiating or triggering one or more alerts or therapeutic deliverymodifications during operation of the medical device.

The treatment catheter 12 may include a handle 110 coupled to theproximal portion 26 of the elongate body 24 and/or the inner elongatebody 70. The handle 110 may include one or more actuation elements 112,such as sliders, levers, or knobs, for manipulating the elongate body24, inner elongate body 70, and/or additional components of the medicaldevice. For example, the handle 110 may include a knob that is inmechanical communication with the inner lumen, such that rotation of theknob may produce a similar rotation of the inner lumen within the mainlumen 32 of the elongate body 24. Additionally or alternatively,rotation of the inner elongate body 70 may be controlled automaticallyor semi-automatically by the control unit 14. For example, the handle110 may include a geared motor controlled by the control unit 14 totransmit movement to the elongate body 70. Alternatively oradditionally, the handle 110 may include a slider, lever, or otheractuation element that is also in mechanical communication with theinner elongate body 70 such that activation of the actuation elementselectively advances or retracts (that is, longitudinally moves) theinner elongate body 70 in at least one longitudinal direction and/orrotates the inner elongate body 70 in a clockwise or counterclockwisedirection. The handle 110 may further include circuitry foridentification and/or use in controlling of the catheter or anothercomponent of the system 10. Additionally, the handle 110 may be providedwith a fitting for receiving a guide wire that may be passed into themain lumen 32 or a guidewire lumen (not shown).

Referring now to FIGS. 6A-6C, various positions of the inner elongatebody relative to the balloon treatment element are shown. Forsimplicity, the delivery lumen 82 and linear segments 88 are not shownas it is in FIGS. 4 and 5. As described above, the inner elongate body70 may include a plurality of apertures 74, each of which correspondingto an elongate body first aperture 64 and a balloon lobe first aperture60. For example, if the balloon treatment element 18 includes six lobes,the inner elongate body 70 may include six apertures. As shown in FIG.6A, the balloon treatment element 18 may be inflated when the innerelongate body 70 is rotated such that the apertures 74 of the innerelongate body 70 are aligned with or correspond to the first apertures64 of the elongate body 24 and the first apertures 60 of the balloonlobes 20. In this configuration, an inflation fluid may be delivered tothe inner chambers 56 of the balloon lobes 20 through the main lumen 32of the elongate body 24, through the apertures 74 of the inner elongatebody 70, through the first apertures 64 of the elongate body 24, andthrough the first apertures 60 of the balloon lobes 20. As shown in FIG.6B and described in more detail below, each balloon lobe 20 may befurther selectively inflated when the inner elongate body 70 is rotatedsuch that the inner elongate body 70 apertures 74 are not aligned withor correspond to the first apertures 60 of the balloon lobes 20 and thefirst apertures 64 of the elongate body 24. In this configuration,inflation fluid within the balloon lobes 20 is prevented from evacuatingthrough the first apertures 60, 64 and further inflation fluid may beprecisely delivered to one or more lobes 20 by one or more linearsegments 88 of the delivery lumen 82. Finally, as shown in FIG. 6C, theinflation fluid may be evacuated and replaced by a cryogenic refrigerantas it flows without affecting the inflation level of each balloon lobe20 when the inner elongate body 70 is rotated such that the innerelongate body apertures 74 are only partially aligned with orcorresponding to the first apertures 60 of the balloon lobes 20 and thefirst apertures 64 of the elongate body 24. In this configuration, theflow rate and/or injection pressure of the cryogenic refrigerant beingdelivered by the delivery lumen 82 to each balloon lobe 20 may bebalanced by the evacuation rate of the fluid from the balloon lobes 20through the inner elongate body apertures 74.

Referring now to FIGS. 7 and 8, examples of asymmetrical inflation ofthe balloon treatment element are shown. As is described in more detailbelow, each balloon lobe 20 may be inflated independently of the othersin order to ensure contact between the balloon treatment element 18 anda variety of target tissue configurations. As is shown in FIG. 7, forexample, the balloon treatment element 18 may be initially inflated andpositioned at a pulmonary vein ostium, or at least partially insertedinto the pulmonary vein. Then, each balloon lobe 20 may be preciselyinflated as needed, depending on the morphology of the pulmonary vein.This may be particularly useful when the pulmonary vein has anon-circular or irregular cross section on which it is difficult toproduce a circumferential lesion with traditional, non-lobedcryoballoons. Likewise, the balloon treatment element 18 may be inflatedto contact a lateral area of target tissue. As shown in FIG. 8, forexample, the balloon treatment element 18 may be initially inflated andpositioned proximate an area of target tissue on a cardiac wall. Then,the balloon lobes that are not in contact with the target tissue may notbe inflated at all and the balloon lobes that are in contact with thetarget tissue may be inflated using the delivery lumen 82 and the linearsegments corresponding to each of the balloon lobes to be inflated.Deflating or not inflating the balloon lobes that are not in contactwith the target tissue may reduce the warming effect of surroundingblood on the balloon treatment element 18.

Referring now to FIGS. 9A-9D, configurations of the inner elongate bodywithin the treatment catheter during a cryotreatment procedure areshown. The treatment catheter 12 may first be navigated through thepatient's vasculature to a target treatment site. As a non-limitingexample, the treatment catheter 12 may be navigated to the left atriumof the patient's heart, to a location at which the balloon treatmentelement 18 is in contact with or proximate a pulmonary vein ostium. Oncethe treatment catheter 12 is at the desired location, the balloon lobes20 may be inflated during a primary inflation cycle. As shown in FIG.9A, during the primary inflation cycle, the inner elongate body 70 maybe positioned such that the inner elongate body apertures 74 are open(that is, such that the inner elongate body apertures 74 are fullyaligned with the first apertures 64 of the elongate body 24 and thefirst apertures 60 of each balloon lobe 20). An inflation fluid may thenbe delivered from the inflation fluid reservoir 38 through the mainlumen 32 of the elongate body 24, from where it passes through theapertures 74 of the inner elongate body 70, the first apertures 64 ofthe elongate body 24, and the first apertures 60 of the balloon lobes20. The inflation fluid may continue to be delivered this way until allof the balloon lobes 20 are inflated and the balloon treatment element18 has an at least approximately circular cross-sectional shape. Anysuitable inflation fluid may be used, such as room-temperature nitrousoxide (N₂O) vapor. As is shown in FIG. 9B, the inner elongate body 70may then be rotated either clockwise or counterclockwise such that theinner elongate body apertures 74 are closed (that is, no longer fullyaligned with the first apertures 64 of the elongate body 24 and thefirst apertures 60 of each balloon lobe 20). In this position, fluidflows from the main lumen 32 into the balloon lobes 20, and evacuationof fluid from the balloon lobes 20 into the main lumen 32, may beprevented. Although not shown, the inner elongate body 70 mayalternatively be moved longitudinally (advanced or retracted) within theelongate body 24 so the inner elongate body apertures 74 are no longeropen or aligned with the first apertures 64 of the elongate body 24 andthe balloon lobes 20.

As is shown in FIG. 9C, inflation fluid may be delivered from theinflation fluid reservoir 38 through the delivery lumen 82 and into eachof the linear segments 88 at the distal portion of the delivery lumen 82in a secondary inflation cycle. The inflation fluid may then passthrough the delivery apertures 98 of the fluid delivery segments 96 andinto the inner chambers 56 of the balloon lobes 20. Due to the closedconfiguration of the inner elongate body apertures 74, fluid passinginto the balloon lobes 20 may continue to inflate, and thereforeincrease the size of, each of the balloon lobes to which the inflationfluid is delivered. As a non-limiting example, the pulmonary vein mayhave an asymmetric morphology. In order to ensure contact between theentire or at least substantially the entire circumference of the balloontreatment element 18, one or more balloon lobes may be further inflatedusing the secondary inflation cycle so that extend farther from thecatheter 12 longitudinal axis than other balloon lobes. In other words,the outer surface of the balloon at the widest portion of some balloonlobes may be located at a greater radial distance from the catheterlongitudinal axis than others. Thus, these larger balloon lobes maybridge the gap between the balloon treatment element 18 and the wall ofthe pulmonary vein. Inflation fluid may be delivered to all or fewerthan all of the balloon lobes 20 during the secondary inflation cycle.

Once the balloon treatment element 18 has the desired configuration andwhile the injection has started, the inner elongate body 70 may berotated clockwise or counterclockwise until the inner elongate bodyapertures 74 are partially open (that is, such that the inner elongatebody apertures 74 are partially aligned with the first apertures 64 ofthe elongate body 24 and the first apertures 60 of the balloon lobes20), which defines the transition phase. Then, the elongate bodyapertures 74 are fully open once the ablation has reached its normalflow and/or pressure. The cryogenic refrigerant may be delivered from acryogenic refrigerant reservoir 36 through the delivery lumen 82 andinto the balloon lobes 20, as the inflation fluid was delivered in thesecondary inflation cycle. During this transitional phase betweeninflation and ablation, cryogenic refrigerant may be injected into theballoon lobes 20 and may gradually replace the inflation fluid, whichmay be evacuated through the first balloon lobe apertures 60 and intothe main lumen 32. Additionally, the main lumen 32 may be in fluidcommunication with a vacuum source 40, which may facilitate evacuationof inflation fluid and cryogenic refrigerant from the balloon lobes 20.The differential injection pressures between the balloon lobes 20 willmaintain the multi-lobe balloon shape during ablation.

If the treatment catheter 12 is navigated to other treatment locations,such as a wall of the left atrium, the balloon lobes that are in contactwith the target tissue may be inflated using only the delivery lumen 82as described above for the secondary inflation cycle. Further, the innerelongate body 70 may be positioned such that the inner elongate bodyapertures 74 are closed. In this manner, fewer than all of the balloonlobes may be inflated.

Referring now to FIGS. 10 and 11, a method of manufacturing amulti-lobed balloon treatment element is shown. Specifically, a lateralcross-sectional view of thermoplastic tubes 114 within a mold 116 forforming the multi-lobed balloon treatment element 18 is shown in FIG.10, and a distal cross-sectional view of the same is shown in FIG. 11. Aplurality of extruded thermoplastic tubes 114, one for each balloonlobe, may be initially bonded to each other in a radial array to form aparison 118 around a core 120 (as shown in FIG. 11) using an adhesive,thermal bonding, laser welding, or the like. The parison 118 may bepositioned within a mold 116 that is shaped similar to the inflatedballoon treatment element 18. Each thermoplastic tube 114 may then beexpanded using compressed air/gas to conform to the shape of the mold116.

It will be appreciated by persons skilled in the art that the presentinvention is not limited to what has been particularly shown anddescribed herein above. In addition, unless mention was made above tothe contrary, it should be noted that all of the accompanying drawingsare not to scale. A variety of modifications and variations are possiblein light of the above teachings without departing from the scope andspirit of the invention, which is limited only by the following claims.

What is claimed is:
 1. A method for ablating tissue, the methodcomprising: navigating a medical device to a tissue region; positioningthe medical device adjacent to the tissue region, the medical deviceincluding: an elongate body including a distal portion with a distalend, a proximal portion, and a lumen therebetween; and a balloontreatment element coupled to the distal portion of the elongate body,the balloon treatment element including a plurality of balloon lobesradially arranged around the elongate body, each of the plurality ofballoon lobes including: an attachment spine affixed to the distalportion of the elongate body; and a first lateral surface and a secondlateral surface, each of the first lateral surface and the secondlateral surface being at least substantially planar, the first lateralsurface of each of the plurality of balloon lobes being in contact withthe second lateral surface of an adjacent one of the plurality ofballoon lobes; and contacting the tissue region with at least oneballoon lobe of the plurality of balloon lobes; inflating the at leastone balloon lobe; and ablating at least a portion of the tissue regionwith the at least one balloon lobe.
 2. The method of claim 1, whereinablating the at least a portion of the tissue region includescryogenically ablating the at least a portion of the tissue region withthe at least one balloon lobe.
 3. The method of claim 1, whereinablating at least a portion of the tissue region includes deliveringradiofrequency ablation energy to at least a portion of the tissueregion with the at least one balloon lobe.
 4. The method of claim 1,wherein ablating at least a portion of the tissue region includesdelivering electroporation energy to at least a portion of the tissueregion with the at least one balloon lobe.
 5. The method of claim 1,wherein each of the plurality of balloon lobes further includes a tissuecontact surface configured to contact the at least a portion of thetissue region.
 6. The method of claim 1, wherein the tissue region is aregion of pulmonary vein ostium.
 7. The method of claim 1, wherein themethod further comprises inflating the balloon treatment element tocontact the at least a portion of the tissue region with a tissuecontact surface.
 8. The method of claim 7, wherein ablating the at leasta portion of the tissue region includes dispersing a coolant inside atleast one of the plurality of balloon lobes.
 9. The method of claim 1,wherein the at least one of the plurality of balloon lobes is in thermalcommunication with the tissue region.
 10. The method of claim 9, furtherincluding a sensor, the sensor configured to monitor at least one of thegroup consisting of pressure, temperature, flow rates, and volume.
 11. Amethod of treating a tissue region, the method comprising: positioning amedical device adjacent the tissue region, the medical device including:an elongate body including a distal portion with a distal end, aproximal portion, and a lumen therebetween, the distal portion of theelongate body including a first plurality of apertures and a secondplurality of apertures located distal to the first plurality ofapertures, each of the first plurality of apertures and the secondplurality of apertures being radially arranged around the elongate body;and a balloon treatment element coupled to the distal portion of theelongate body, the balloon treatment element including a plurality ofballoon lobes radially arranged around the elongate body, each of thefirst plurality of apertures and the second plurality of aperturescorresponding to one of the plurality of balloon lobes, each of theplurality of balloon lobes including: an attachment spine affixed to thedistal portion of the elongate body; a tissue contact surface oppositethe attachment spine; and a first lateral surface and a second lateralsurface, each of the first lateral surface and the second lateralsurface being at least substantially planar, the first lateral surfaceof each of the plurality of balloon lobes being in contact with thesecond lateral surface of an adjacent one of the plurality of balloonlobes; and contacting the tissue region with at least one balloon lobeof the plurality of balloon lobes; inflating the at least one balloonlobe; and ablating at least a portion of the tissue region with the atleast one balloon lobe.
 12. The method of claim 11, wherein ablating theat least a portion of the tissue region includes cryogenically ablatingthe at least a portion of the tissue region with the at least oneballoon lobe.
 13. The method of claim 11, wherein ablating at least aportion of the tissue region includes delivering radiofrequency ablationenergy to at least a portion of the tissue region with the at least oneballoon lobe.
 14. The method of claim 11, wherein ablating at least aportion of the tissue region includes delivering electroporation energyto at least a portion of the tissue region with the at least one balloonlobe.
 15. The method of claim 11, wherein ablating the at least aportion of the tissue region further includes dispersing a coolantinside the at least one balloon lobe.
 16. The method of claim 15,wherein each of the first and second pluralities of apertures beingradially arranged around the elongate body correspond to one of theplurality of balloon lobes.
 17. The method of claim 16, wherein at leastone of the plurality of balloon lobes is in fluid communication with atleast one of the first plurality of apertures and at least one of thesecond plurality of apertures, and the method further comprisesmanipulating a direction of the coolant dispersion based at least inpart on the position of the first plurality of apertures and the secondplurality of apertures.
 18. The method of claim 17, wherein the medicaldevice further includes an inner elongate body disposed within theelongate body, the inner elongate body having a proximal portion and adistal portion defining a distal end, the distal end of the innerelongate body being distal to the first plurality of apertures of theelongate body.
 19. The method of claim 11, further including deflatingany balloon lobes that are not in direct contact with the at least aportion of the tissue region.
 20. The method of claim 11, wherein atleast a portion of the plurality of balloon lobes may be inflated to afirst inflation pressure and at least a portion of the plurality ofballoon lobes may be inflated to a second inflation pressure.